WDPN33 PGTW 282100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (NEOGURI) WARNING NR 042//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 40.3N 169.7E
   INITIAL INTENSITY: 95 KTS
   GEOGRAPHIC REFERENCE: 1270 NM NORTH OF WAKE ISLAND
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 31 KTS
   SIGNIFICANT WAVE HEIGHT: 38 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TYPHOON (TY) 25W CONTINUES TO EXCEED EXPECTATIONS, MAINTAINING A
WELL-DEFINED EYE EMBEDDED WITHIN A SYMMETRICAL CDO, EVEN IN THE
FACE OF OTHERWISE HIGHLY UNFAVORABLE CONDITIONS. ANIMATED ENHANCED
INFRARED (EIR) SATELLITE IMAGERY SHOWS THAT WHILE THE EYE HAS
PERSISTED, IT HAS STEADILY SHRUNK IN SIZE AND BECOME STEADILY MORE
CLOUD-FILLED. AS OF THE 2000Z HOUR, THE EYE IS NO LONGER EVIDENT IN
THE VISIBLE IMAGERY, THOUGH THE VERY LAST VESTIGES OF THE
UPPER-LEVEL EYE REMAIN EVIDENT IN THE EIR. A 281706Z SSMIS 89GHZ
MICROWAVE IMAGE REVEALED A MICROWAVE EYE FEATURE, THOUGH THE
SOUTHERN HALF OF THE EYEWALL IS EXTREMELY SHALLOW, WHILE THE
NORTHERN PORTION REMAINS QUITE ROBUST. THIS IS A REFLECTION OF THE
VERY HIGH SHEAR (35-40 KTS) COMING IN FROM THE SOUTH-SOUTHWEST; 
HOWEVER, THE SHEAR VECTOR IS IN PHASE WITH THE STORM MOTION, 
THEREFORE THE EFFECTS HAVE FAR BEEN LIMITED. BUT THAT IS ABOUT TO 
END, IMMINENTLY. THE INITIAL POSITION IS ASSESSED WITH HIGH 
CONFIDENCE BASED ON THE 20-NM EYE IN THE EIR AT THE TIME. THE INITIAL 
INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE, BASED ON A BLEND OF 
AVAILABLE SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES NOTED BELOW. 
ENVIRONMENTAL CONDITIONS ARE HIGHLY UNFAVORABLE, WITH VERY HIGH SHEAR 
APPROACHING 40 KNOTS, VERY COOL SSTS, OFFSET BY ROBUST POLEWARD 
OUTFLOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: NORTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED TO THE SOUTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   RJTD: T6.0 - 115 KTS
   RCTP: T5.0 - 90 KTS
   KNES: T6.0 - 115 KTS
   CIMSS SATCON: 94 KTS AT 281512Z
   CIMSS ADT: 99 KTS AT 281730Z
   CIMSS AIDT: 103 KTS AT 281730Z
   CIMSS D-MINT: 95 KTS AT 281421Z
   CIMSS D-PRINT: 82 KTS AT 281900Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 30+ KTS
   SST: 20-22 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: RAPIDLY STRENGTHENING THERMAL ADVECTION AND DRY
AIR ENTRAINMENT. 

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TY 25W IS FORECAST TO TRACK NORTHEASTWARD,
THEN EASTWARD OVER THE COURSE OF THE FORECAST PERIOD, AS IT MOVES
AROUND TO THE NORTH OF THE LARGE SUBTROPICAL RIDGE TO THE
SOUTHEAST. THE SYSTEM IS IN INITIAL PHASE OF A FORECASTED RAPID
WEAKENING PHASE, WITH THE SHEAR ALREADY STARTING TO IMPACT THE
SYSTEM. THIS TREND WILL ACCELERATE OVER THE NEXT FEW HOURS, WITH
MODEL CROSS-SECTIONS DEPICTING VORTEX DECAPITATION WITHIN THE NEXT
12 TO 18 HOURS. THE SYSTEM IS ALSO IN THE EARLY PHASES OF
EXTRATROPICAL TRANSITION (ETT), WITH RAPIDLY INCREASING THERMAL
ADVECTION DRIVING FRONTOGENESIS, AS SEEN IN ANIMATED SHORTWAVE
INFRARED (SWIR) AND PROXY VISIBLE (PROXYVIS) IMAGERY. THE SYSTEM IS
EXPECTED TO RAPIDLY WEAKEN WHILE COMPLETING ETT WITHIN THE NEXT 24
HOURS.

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN GOOD AGREEMENT
WITH MINIMAL SPREAD, LENDING HIGH CONFIDENCE TO THE JTWC TRACK
FORECAST, WHICH IS PLACED NEAR THE CONSENSUS MEAN. INTENSITY
GUIDANCE IS ALSO IN GOOD AGREEMENT, THOUGH LIKELY WEAKENING THE
SYSTEM TOO QUICKLY. THUS THE JTWC FORECAST IS PLACED SLIGHTLY
HIGHER THAN THE CONSENSUS MEAN THROUGH THE FORECAST, THOUGH
CONFIDENCE REMAINS HIGH. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: HIGH//
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